This invention generally relates to the field of computer system assemblies and more particularly to the assembly of circuit boards contained therein.
The increased packaging densities in today's computer assemblies along with the increase in market demand for lower profile personal computer system units has fostered the use of riser card assemblies for attaching peripheral cards to a computer system. Some such assemblies are designed such that peripheral cards attach to respective connectors on one side or on both sides of the riser card.
As shown in FIG. 1, a prior art riser card assembly 100 uses both sides of the riser card for placing staggered peripheral card connectors on the sides of a riser card. The assembly 100 includes a main circuit board 102 upon which a universal connector 105 is placed. A conventional riser card 110 with electrically conductive metallic circuit traces having a mating connector is attached to the connector 105 which holds the riser card 110 in an upright position. As shown, the riser card 110 has opposing sides 111 and 112 where each side includes one or more staggered peripheral card connectors 150 for receiving a corresponding number of peripheral cards 130. Each peripheral card 130 has a component side 131 where the electronic circuitry in the form of integrated circuit chips and discrete components are placed thereon. As depicted, the component side 131 of the peripheral cards 130 plugged into first side 111 of riser card 110 face a downwardly direction, where as, the peripheral cards 130 with components side 131 plugged into second side 112 face an upwardly direction. The conventional staggered connector arrangement utilizes connectors having rows of pins 151 which attach to the riser card via corresponding conductive through-holes formed on the opposing surfaces of the riser card 110.
However, with increased demand for lower profile computer system units, the staggered technique for placement of peripheral card connectors on either side of the riser card no longer permits the achievement of the desired packaging densities.
Furthermore, with the advent of other bus architectures such as PCI and VESA, known as local bus implementations which may be combined with other personal computer buses such as ISA, there is a need for a single computer system that supports a plurality of peripheral cards having differing form factor specifications.